Ecochard, R., Duterque, O., Leiva, R., Bouchard, T., & Vigil, P. (2015). Self-identification of the clinical fertile window and the ovulation period. Fertility and Sterility, 103(5), 1319–1325.e3.
Key Results
The self-identification of the biological fertile window by the observation of any type of cervical mucus provides 100% sensitivity but poor specificity, yielding a clinical fertile window of 11 days. However, the identification of the biological fertile window by peak mucus (defined as clear, slippery, or stretchy mucus related to estrogen) yielded 96% sensitivity and improved specificity. The appearance of the peak mucus preceded the biological fertile window in less than 10% of the cycles. Likewise, this type of mucus identified the ovulation window with 88% sensitivity.
Conclusion
These results suggest that, when perceived accurately, more accurate clinical self-detection of the fertile window can be obtained by identification of peak mucus. This may improve efforts to focus intercourse in the fertile phase for couples with fertility concerns.